Descriptions

The influence of evaporative cooling for delay of 'Bartlett' and
'Bosc' fruit bud development for frost avoidance was investigated.
Two mist systems, one in a mature pear orchard and the other in a
young pear hedgerow, delayed 'Bartlett' and 'Bosc' bloom up to 15 and
8 days respectively. A low pressure sprinkler system delayed
'Bartlett' bloom 14 days and 'Bosc' bloom 8 days. Bloom delay
resulted in increased set, seed count, and fruit growth rates. Return
bloom was reduced in the mature orchard 'Bartlett' mist and 'Bosc'
sprinkler plots in 1976 and this resulted in reduced cropping the following
year. Fruit sizes were reduced 6% for 'Bartlett' and 12% for
'Bosc' while harvest maturity was delayed 0 to 6 days and 2 to 7 days
respectively. Soluble solids were lowered in the misted hedgerow.
Titratable acid was not affected by the bud development delay. Foliar
N levels were reduced in the water treated plots. Pear psylla activity
was delayed by misting while fire blight produced 36 strikes in 1976.